The purpose of the project is to systematically study (a) coronavirus molecular structure and (b) the molecular biology of coronavirus replication. The coronaviruses which cause gastroenteritis in the calf (bovine coronavirus) pig (transmissible gastroenteritis virus) and the coronavirus which causes an encephalitis in pigs (hemagglutinating encephalitis virus) will be studied first. They can be cultured in vitro to greater than 10 to the 8th power infectious particles/ml. Radioactively labeled polypeptides, glycopolypeptides, and ribonucleic acids, will be analyzed using gel electrophoresis. A virion associated RNA-dependent RNA polymerase will be sought. Virion RNA, intracellular virus-specific RNA, and polymerase product (if found), will be analyzed for size, strandedness (single or double), polyadenylation, and a 5'-methylated cap structure of the type in m7G5ppp5'Nmp. Antiserum will be prepared against purified viruses and viral components.